Filament sorting apparatus



June 8, 1943- D. E. ELMENDORF FILAMENT SORTING APPARATUS Filed' Sept. 26, 194d 7 2 Sheets-Sheet 1 M 0 d am 1% w! ml m m v A wmw .5 H3 H7 WI U b June 1943- Dr. ,E. ELMENDORF 2,321,191

FILAMENT SOfiTING APPARATUS Filed Sept. 26, 1940 2 Sheets-Sheet 2 Invenfor Dur ea E.Elmendor+,

His A't'torne Patented June 8, 1 943 FILAMENT SORTING APPARATUS Duryea E. Elmendorf, Cleveland, Ohio, assignor a to General Electric Company, a corporation of New York Application September 26, 1940, Serial No. 358,565

3 Claims.

My invention relates to the manufacture of incandescent lamps and more particularly to apparatus for automatically sorting lamp fila- -ments according to length.

Present day incandescent lamps are quite sensitive in their characteristics to very minute differences in length of the filaments since the said filaments are of concentrated form, generally coiled or coiled-coil, and they materially affect the operating conditions of the lamps if improperly proportioned. On the other hand, it is not always possible to manufacture filaments commercially to the exact specifications desired in present manufacturing practices. For instance, the filaments are likely to be made with variations in the pitch of their coils and with corresponding variations in overall length although containing the specified amount of wire.

Such filaments are satisfactory if these variations are considered and proper allowances made,

in the mounting thereof so that they have the desired effective length. Modern high speed mounting apparatus is constructed so that any appreciable variation in length of the filaments prevents them from being handled satisfactorily. It is therefore desirable to separate filaments of different lengths into groups and to use each group in mounting apparatus adjusted to handle that particular group.

The principal object of my invention is to provide apparatus for automatically sorting filaments into groups of very limited variations in length.

Another object of my invention is to provide automaticsorting apparatus of such extreme sensitivity as to permit its use in separating coiled, coiled-coil and other shaped filaments as to length. Coiled, coiled-coil and other shaped filaments are comparatively flexible and therefore very diflicult to measure accurately.

Other objects and advantages of my invention will appear from the following detailed description of a species thereof and from the accompanying drawings. 1 In the drawings Fig. l is a plan view of apps- The sorting apparatus disclosed in the draw-- ings is combined with a table Ill, only partially shown in Figs. 1 and 2, which forms the means of receiving the filaments II. An operator is 1 stationed adjacent the forward edge of the table II and, in the usual procedure, places a quantity of the'filaments II in a single .pile thereon and I then separates said filaments from each other with the aid of a pair of tweezers. filaments II can then be inspected under the addi tional illumination provided above and below the frosted glass plate insert I2 in the work surface of the table III. The said filaments are then transferred one at a time to the moving buckets I3 passing from left to right along the back edge of the table. The buckets I3 are mounted at regular intervals along a chain I4 extending around the sprockets I5 and H5 at opposite ends ofthe device and form parts of a carrier by which the filaments are advanced thru the sorting apparatus of the device.

Each filament II must reach the sorting apparatus separately in order that it be treated without interference from any of the others, and the operators procedure is to inspect a single filament at a time and then transfer said filament to the bucket I3 which is located adjacent the table III at that particular moment. The filament I I must lie in a normal relaxed position in the bucket I3 so that it extends, to its true length and is placed into the trough formed by the fixed and movable sections ll and I8 respectively thereof which keep it in a straight line. The fixed section I! of the bucket I3 is fastened directly to block I9 on a special link 20 of the chain I4 whereas the movable section I! thereof is pivoted on the screw 2I extending from said block I9 and is -so distributed thereabout that it swings against the fixed section I! by its own weight and forms the trough. The buckets I3 are shorter than the filaments II and in their course of movement are carried between the stationary guide bars 22 and 23 which assist the operator in positioning the filaments I I centrally therein. The guide bars 22 and 23 are mounted on a portion 24 of the frame 25 of the device which extends between the upper and lower sections of the chain I4 and only roughly position the filament -II so that the central coiled-coil portion in this instance is wholly contained within the bucket I3 while the ends of the filament, which are of single coil form, extend from the opposite ends of the bucket.

The order of movement of the carrier which advances the buckets II from left to right at a uniform speed is created by the driving force of an electric motor and speed reducer (not shown) coupled to the shaft 26 supporting sprocket I. The shaft 26 i mounted in a bearing 21 held by a vertically extending portion of the frame 25 of the device and corresponds to shaft 2. supporting sprocket I! which is similarly supported. Midway in front of the table II the chain ll passes between the upper and lower guide rails II and II respectively (Figs. 1, 2 and 3) which keep it in a straight path of movement, and shortly thereafter the block I! thereon slides onto-the rest 32 extending from rail'll which keeps the bucket I3 up inplace.

The sorting apparatus a is located to the right of the table I iii-the path of movement oi the gradually narrowingpath of definite width which the filament must bridge at some point. Dar contact 34 is mounted to one side of the path of movementof the bucket l3 whereas the other bar or segment contacts 35, 33, 31 and 33 are mounted one after the other along the oppositeside of .said path and are nearer the bar segment 34 so as to reduce the width of said path by very minute steps all within the normal range of length of the filaments Normally the filament entering the sorting apparatus is not located in the exact center of the bucket l3 andit engages either the bar contact 34 or segment contact 35 first and is moved endwise in the bucket l3. If the filament II is then of greater length than the spacing between the contacts 34 and 35, it will complete an electrical circuit therebetween which will cause it to be dropped from the bucket l3 before said bucket I3 is moved further along the path. Most generally however, the filament does not have a length equal to the width of the spacing between the contacts 34 and 35, and it is carried further along by the bucket l3. In this, particular instance each of the succeeding segment contacts 33, 31 and 33 are .5 mm. nearer the bar contact 34 than the segment contact 35 and the filament I I will finally reach a point where it will complete a-circuit between the bar contact 34 and one of thesegment contacts 33, 31 or 33 and be dropped from the bucket l3.

The electrical means connected to the contacts 34, 35, 35, 31 and 33 brings about the release of the filament II by causing the movable section l3 of the bucket |3 to be tipped away from the fixed section |1 thereof so that said filament ll falls free of said bucket l3. The release of the filament II is effected almost immediately after it completes the circuit between the. contacts so that it will fall through an opening in the block 33' and into'the particular container 33, 43, 4|, or.42 located below thesegment contact 35, 33, 31'or 33 which it has engaged. This arrangement of the containers 33, 43, 4| and 42 causes each to receive only filaments of one length. Since the position ofthe bucket I 3 at the moment the circuit is completed controls the.

distribution of the filaments II, the first container 33 .in the series receives all filaments ll of greater than the established maximum length and the three following containers 43, 4| and .42.receive, filaments progressively shorter in .5 mm. steps. The movable section I3 istipped by g a downward movement or the metal bar 43 which extends over each of the sorting stations and which engages the finger 44 attached to said movable section'|3.. The metal bar" is supported by the studs 45 which engage the ex- .tended ends of the arm 43 and .the lever 41 which, in turn, are attachedto the horizontal rod 43 held by the brackets 43. The brackets 43 are mounted on the upper edge of the verticallydisposed plate 53 running parallel to the ccnterportion ofthe carrier which is attached 54 which rests on the table to an upstanding flange on the frame 23'and which is the common means or support for the guide rails 30 and 3| and the insulating block .33. If the filament is so short that it passes between the, last segment contact 33 and the bar contact 34 without completing the circuit therebetween, it is released when the finger 44 engages I the stationary cam 5| and opens the bucket |3 during the normal movements thereof. The cam 5| is stationary and is supported by the stud 52 which enga es the arm 53 fastened to the upper surface of the plate 53. The filaments released at this station fall to the container 5 in the manner of the other containers 33, 43, 4| and 42 and are all shorter than the established minimum. The

. four guides, 53 on the upper surface of the table 55 keep the containers 33, 40, 4|, 42 and 54 in place and yet permit them to beremoved so that they can be emptied. The containers 33, 43, 4|, 42 and 54 form the segregating means for the filaments The bar contact 34 and the segment contact 33, 33, 31 and 33 together with the other electrical means provide a particularly effective and desir able means of sorting the filaments II in that said means is extremely sensitive and is capable of measuring the filaments without bending or applying force to them in any way. The filament being or relatively slight cross-section and of considerable length, is very flexible and is difiicult to measure in a freeunstrained condition.

Exceptingthe contacts 34, 35, 33, 31 and 33,

the electrical means is comprised of two main parts; one of which is the discharge tube control means which detects when the filament completes an electrical circuit between the contacts located at each station; and the other of which is the means of supplying the necessary currents to the control means. The electrical connections are such that the primary 51 of the transformer 53 of the current supply means is connected to the line, and the secondaries 53, 33 and 3| thereof are connected to the heater of the Thyratron discharge tube 33, the plates (anodes) of the rectifier tube 33 and the athode of said rectifier tube 33 respectively. A center tap on the secondary 53 of the transformer 53 is connected to the cathode of the Thyratron 32. The resistances 34 and 35 and potentiometer 33 adjust the voltage of the current supply to suit the requirements of the Thyratron control means and the condenser 31 smooths out the current.

-When a filament II is not in the detecting circuit, the voltage drop across the resistance 34 causes the grid of the Thyratron to be sumciently negative with respect to the cathode thereot to prevent the flow of current from said cathode to the plate '(anode) and the current supply-proceeds. in charging the condenser 33. If however only a very brief connection is made between the bar contact 34, which is. connected through resistance 33 to'the cathode of the Thyratron, and

one of the segment contacts 35,33, 31 or 33, which are all connected together by the metal strip 13 and to the grid of the 'I'hyratron, the grid is made less negative and current flows between cathode and plate (anode), The plate (anode) o1! the Thyratron is connected through the actuating coil of the relay 1| to the current supply and the condenser 33 and any flow of current in this circuit operates the relay 1| which connects the solenoid 12 to the The solenoid 12 in turn provides the means of lowering the bar 43 and opening the bucket ii. The condenser 68 gives up the current required to create the flow or current through the Thyratron 82 and the relay 'H 4 and is soon discharged whereupon the voltage drop across the resistance 88 is such that said Thyratron 62 will no longer pass current. When the fiow of current ceases due to the exhaustion of the condenser 68 the current supply immediiately begins to recharge said condenser 88 as the grid is again in control of the Thyratron. If. the detecting circuit is complete when the condenser 68 becomes fully charged, the cycle of events is repeated causing the relay II and the solenoid 12 to be operated again.

In event it is desired to change the speed with which the cycles of operation of the detecting means are repeated, the potentiometer 66 can be adjusted to apply more or less voltage to the condenser 68 so that it is charged with more or less rapidity. The resistance 13 in the current supply lead to the grid causes the negativ grid bias to be reduced to nearly zero voltage very quickly even though the connection between the filament H and one or both of the contacts is very poor and has considerable resistance. The ground connection 14 which is made to the frame 25 of the device through the resistance 15 prevents any electrical charge being built up in the frame 25 from leaking off through the buckets I3 and the filament II in such a manner as to disturb the operation of the device.

The condenser 16 and resistance 'l'l shown ad jacent the relay H are for reducing arcing at the contacts thereof and for reducing the fiow of current in the circuit controlled thereby to reduce the speed or operation of the solenoid 12 respectively.

The solenoid 12 is mounted adjacent the rearwardly extending end of the lever 41 on the up ture l9, brought about by the solenoid 12, lowers the bar 43.

The sorting and counting means are operated in combination with each other as the downward motion of the bar 48 causes the filament to be registered on one of four counters 8! (only two oi which appear in Fig. 2) mounted on the board 82 should the filament ll be dropped in one oi. the first four containers 39, 48, 4| and 42. The counters 8| are commercially available products and are operated by independent electrical circuits controlled by a like number of pairs or contacts on the bar 88 of insulation carried by the bar 48. The contacts are located on the bar 83 in such a manner that the insulation button '84 on the lower contact 88 of each pair strikes the block I! supporting the bucket II when said bucket i8 is below that particular pair oi! contacts and the bar 43 is moved down. ,Each of these contacts 88 are connected to one or the counters 8| through a screw 88 held by bar 88 and are bent upward into engagement with the other contact 81 of each pair by engagement with the block l8. In this manner the side or the line connected to contact I! by means or a wire and the metal strip 88 is connected to contact 88 and the counter 8|, and said counter ll is actuated since it is already connected to the other side or the line. The metal strip 88 extends along the lower surface of the insulating bar" 88 and connects each or the upper contacts 81 together, An insulating sleeve .there is no connection therebetween.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A device for sorting flexible filaments according to length comprising a carrier for supporting a filamentand advancing it to each of a plurality of stations in turn, means located at each succeeding station providing a pair of spaced fixed contacts for making electrical connections to the ends of "the filament, said pairs of contacts forming a gradually narrowing path of a width corresponding to the normal range in length of the filaments, and means for releasing the filament from the carrier upon engagement of its ends with both contacts of onerpair to complete an electrical circuit therebetween comprising a condenser connected across an electronic control tube. means for charging said condenser, said tube having a grid connected to each pair of contacts for activating the tube when a filament bridges a pair of contacts, such activation causing a discharge of the condenser through the tube,

and means actuated by the discharge of the condenser for releasing the filament from the carrier.

2. A device for sorting filaments according to length comprising a carrier for supporting a filament and advancing it to each of a plurality'oi stations in turn, means located at each succeeding station providing a pair of spaced contacts for making electrical connections to the ends of the filament, said pairs of contacts forming a gradually narrowing path of a. width corresponding to the normal range in length of the filaments, and means for releasing the filament from the carrier upon engagement of its ends with both contacts of one pair and completion oi an electrical circuit therebetween comprising a condenser, a discharge tube having a cathode, anode and control grid, the cathode, and anode being connected to opposite sections of said condenser, means for charging said condenserand providing sufllcient negative bias to the control 'grid to prevent a discharge in said tube, electrically operated means connected between the anode and one section of the condenser for releasing the filament from the carrier, and means connecting one contact or each pair to the control grid and the other to said last-mentioned means so that the completion or a circuit between any one pair of contacts reduces the grid bias and causes a discharge to occur between anode and cathode to'.discharge the condenser and actuate said release means.

3. In a device for sorting filaments according to I length. spaced fixed'contacts'means for carrying the filaments between said contacts to bridge for charging said condenser and providing sure ficient negative bias to the control grid to normally prevent a current flow through the tube and the coil, and an electrical circuit including the said contacts and the grid for reducing the grid bias when the circuit is completed by the bridging of a filament across the contacts to cause the condenser to discharge and energize said coil.

DURYEA E. ELMENDORF. 

